Polyurethane-11 is a synthetic polymer engineered to create a resilient, flexible, and waterproof shield on the surface of the skin, hair, and nails. Its primary function is to enhance the longevity and wear-resistance of color cosmetics and hair styling products without the stiffness associated with traditional resins.
- INCI Name:
- Polyurethane-11
- Chemical/Scientific Name:
- Adipic acid, 1,4-butanediol, isophthalic acid, methylene bis-(4-cyclohexylisocyanate), neopentyl glycol, and trimethylolpropane copolymer.
- Common Aliases:
- PU-11, Polyurethane Resin, Film-Forming Polymer.
| Category: | Texture Enhancers |
| Source Origin: | Synthetic |
| Comedogenic Rating: | 0 |
| Primary Industries: | Color Cosmetics, Hair Care, Nail Care |
| Solubility: | Oil-soluble or dispersible in organic solvents (e.g., Isododecane) |
At a Glance: Properties & Effects
| Texture Enhancement: | |
| Formula Stability: | |
| Irritation Risk: | |
| Comedogenicity: |
- Primary Benefits: Exceptional film flexibility, long-wear durability, water and transfer resistance, non-tacky finish, and improved pigment suspension.
- Potential Risks: Requires dedicated oil-based cleansers for removal; environmental persistence in specific solid forms (e.g., glitters).
Biological Action & Cosmetic Profile
The molecular structure of this ingredient consists of carbamate linkages that facilitate high-performance film formation upon application. These polymers are characterized by their ability to form a “breathable” yet occlusive lattice, which prevents the evaporation of volatile solvents while locking pigments onto the skin. Because the polymer possesses a high molecular weight, it remains on the surface of the stratum corneum and does not undergo percutaneous absorption.Formulators prioritize this specific polyurethane due to its “soft-segment” and “hard-segment” chemical architecture. The hard segments provide structural integrity and resistance to mechanical abrasion, while the soft segments offer elasticity. This balance ensures that makeup moves naturally with facial expressions rather than cracking or flaking. In hair care, this mechanism provides a “memory effect,” allowing hair to maintain a style while remaining soft to the touch.Adhesion is a secondary but critical trait. This polymer exhibits a strong affinity for biological surfaces, significantly reducing the “transfer” of foundations and lipsticks onto clothing or masks. When paired with volatile carriers such as Isododecane or Cyclopentasiloxane, the ingredient facilitates a rapid drying time, leaving behind a smooth, weightless finish.
Broader Applications & Origins
While widely utilized in liquid foundations, this ingredient is also a staple in the production of cosmetic glitters and pearlescent pigments. In these applications, it serves as the coating material that encapsulates Mica or aluminum particles, ensuring they adhere to the skin without fallout. Modern manufacturing techniques emphasize the removal of residual monomers, such as isocyanates, to ensure the finished resin is chemically inert.
Routine Integration
- Synergies: High compatibility with volatile solvents like Isododecane, mattifying agents like Silica, and various silicone derivatives for a seamless glide.
- Conflicts: Poorly compatible with strictly water-based cleansers; double-cleansing with an oil or balm is mandatory for complete removal.
Clinical Consensus & Safety
The Cosmetic Ingredient Review (CIR) Expert Panel assessed 66 polyurethane ingredients and concluded that Polyurethane-11 is safe for use in cosmetics. Dermatological data indicates that the large size of the polymer molecules precludes skin penetration, minimizing the risk of systemic toxicity or sensitization. Furthermore, the Panel verified that residual monomers—including diisocyanates, which are known irritants in their raw state—are not detectable in finished cosmetic-grade polyurethanes. Recent EU regulations (2023/2055) regarding synthetic polymer microparticles (SPM) focus on solid, non-degradable particles; however, when used as a film former dissolved in a liquid matrix, Polyurethane-11 typically remains outside the scope of “microplastic” bans in the European Union.
Is Polyurethane-11 a microplastic?
Regulatory definitions vary by region. Under the latest EU REACH restrictions, it is considered a microplastic if used in solid particle form (like glitter). If it is fully dissolved in a liquid formula, it generally does not meet the “particle” criteria for the ban.
Will this ingredient clog my pores?
No. Clinical assessments confirm that Polyurethane-11 has a comedogenic rating of 0. As an inert polymer, it sits on the surface of the skin and does not interact with sebum or follicular structures.
Why is Polyurethane-11 used in hairspray?
It provides a flexible hold that is resistant to humidity. Unlike older resins that leave hair feeling “crunchy,” this polymer allows for movement and can be easily brushed out without damaging the hair cuticle.